Tehran's repression has intensified in the run up to today's 14 June presidential poll, with escalating pre-emptive arrests of opposition activists. The Islamist regime is terrified of a repeat of the 'people power' protests that threatened the dictatorship in 2009.

Two candidates from the 2009 election for president - Hossein Mousavi and Mehdi Karroubi - remain under house arrest four years later.

By international standards, the election is not free and fair. Candidates are vetted by the Guardian Council and all democratic, liberal, secularist, left-wing and women candidates are banned. The media is censored. There is no open political debate. Dissenting opinions are suppressed and liable to result in arrest.

The real figure may be much higher because prisoners can be held in secret without charge or trial.

The Campaign to Free Political Prisoners in Iran (CFPPI) has launched a petition urging freedom for political detainees, which you can sign here.

Following the disputed 2009 election, which was supposedly 'won' by President Mahmoud Ahmadinejad, hundreds of thousands of opposition Green movement activists staged mass street demonstrations to protest against the rigged official results. They were violently attacked by the police and pro-government militias who killed dozens of protesters and arrested several hundred more.

Writing in the Guardian, Saeed Kamali Dehghan reports that those still in jail include at least 391 students, 90 teachers and professors, 65 writers, poets and film-makers, 20 lawyers and 131 identified as journalists or bloggers.

In addition, almost 1,900 prisoners are either awaiting sentencing or the details of their jail terms have not been publicly disclosed. Most of them were sentenced under vague charges, such as anti-State propaganda or acting against god or national security. Nearly all were denied adequate legal representation.

Of the religious and ethnic minorities in Iranian prisons, at least 572 are Kurds, 203 Arabs, 192 Azeris, 240 Baha'is, 13 Baluchs, 40 Christians, 98 Sufis, two Zoroastrians and one Jew, the Guardian's research shows.

Human Rights Watch reported in March 2008 that an Iranian parliament member, Hossein Ali Shahryari, confirmed that 700 people were awaiting execution in Sistan and Baluchistan province, which is only one of Iran's 30 provinces. Hardly any of these people were documented in official records. Many of them were likely to be members of the severely persecuted Sunni and Baluch minorities. This tends to suggest that the figure of 2,600 political prisoners is probably an under-estimate.

According a report by the Campaign to Free Political Prisoners in Iran (CFPPI):

Presently thousands of political prisoners are held in Iran, without charges or trials. These prisoners range in age from 13-75 years old, and their crimes vary from possessing a book or an article to participating in protests. Prisoners are mercilessly tortured until a confession is obtained, after which most are executed secretly without the knowledge of their families.

Among these political prisoners are lawyers who have tried in vain to defend prisoners, human rights activists, women's rights advocates, journalists, bloggers, workers organising trade unions, Jews, Christians, members of banned opposition groups and the people of the Baha'i faith. Imprisonment and execution trials in Iran are usually held secretly where sentencing for both imprisonment and death are based on trials in absence of defense lawyers, witnesses, evidence or even real charges and sometimes last only a few minutes.

Most sentences passed by the Iranian judiciary system are illegal under international law. Once arrested, proving one's innocence is futile, as unbearable torture methods are routinely used to extract the desired confession.

The regime uses brutal force to purge the populace of all anti-government thought.

The majority of executions are based on the charge of "Moharab" or "enmity of God" and "Corruption on earth". For example, if a teenager was in possession of an article written by a banned opposition party, he / she will be executed on charges of Moharab - usually after days, maybe months, of being subjected to the harshest, most antiquated torture methods in order to extract a confession.

Torture is used routinely in order to extract the desired, dictated confession so that the executions appear justified. Many prisoners are also forced to do a televised confession.

Other times, the Iranian government insists that the executed individuals were "drug smugglers", "rapists" "homosexuals" or "apostates", which are punishable by death under Islamic law.

Iran has 131 offenses punishable by death; among them homosexuality, adultery and drug possession/trafficking. Adulterers are buried to the chest or waste and are slowly stoned to death. Many offenses such as premarital sex are punished with 100 lashes, killing some victims half way through. Juvenile offenders are not spared.

All the executed victims in Iran, whether their death was decades ago or last week, have one thing in common: one day they were arbitrarily deprived of their lives and their most basic human rights. They were often sent to the gallows on the unfathomable charge of "enemy of God".

Between 1981 and 1988, tens of thousands of prisoners were executed and hastily buried in mass graves. They were either shot or hanged cruelly from cranes, where the victim is slowly hoisted up, rendering the most painful suffocation. The ages of the victims ranged from 12 to 70 years old. Although these executions have never stopped; the 1980's massacres were unprecedented in Iranian history and were the subject of a 145 page report by the prominent human right lawyer and UN jurist, Mr. Geoffrey Robertson.

An example of the regime's brutality is Miss Zahra Kazemi; an Iranian born Canadian journalist who was accused of espionage and died in custody under torture in 2003. According to Dr. Azam who had examined the body in Iran before fleeing to Canada in 2005; Miss Kazemi's body had shown signs of brutal torture including skull fractures, a ruptured ear drum, broken ribs and fingers, a crushed toe, severe abdominal bruising, extensive damage to the genitals, missing finger nails and evidence of flogging on the legs and back. She was 52 years old. Another Iranian expatriate, Ms Zahra Bahrami, a Dutch citizen, was tortured for nearly one year before being secretly hanged in January 2011 for participating in a protest.

The regime in Iran has continued to terrorize its people, carry out mass executions of political prisoners, fund terror-supporting organisations such as Hezbollah and orchestrate bombings and assassinations abroad.

Amnesty International, Human Rights Watch, United Nations and Reporters Without Borders have 863, 298, 62 and 56 reports respectively on the gross human rights violations by the Shia Islamist regime. The prominent UN jurist Mr. Geoffrey Robertson QC presented a 145 page report on the 1988 massacre of the political prisoners in Iran.

On March 2012, Mr. Ahmad Shaheed, the UN Special Rapporteur for Iran, presented a detailed report on this issue as well. All these reports confirm and reconfirm massive human rights by the government in Tehran, in contravention of international human rights law.